Electronic Modulation of Metal–Organic Frameworks by Interfacial Bridging for Efficient pH‐Universal Hydrogen Evolution

Abstract

Designing well-defined interfacial chemical bond bridges is an effective strategy to optimize the catalytic activity of metal-organic frameworks (MOFs), but it remains challenging. Herein, a facile in situ growth strategy is reported for the synthesis of tightly connected 2D/2D heterostructures by coupling MXene with CoBDC nanosheets. The multifunctional MXene nanosheets with high conductivity and ideal hydrophilicity as bridging carriers can ensure structural stability and sufficient exposure to active sites. Moreover, the Co-O-Ti bond bridging formed at the interface effectively triggers the charge transfer and modulates the electronic structure of the Co-active site, which enhances the reaction kinetics. As a result, the optimized CoBDC/MXene exhibits superior hydrogen evolution reaction (HER) activity with low overpotentials of 29, 41, and 76 mV at 10 mA cm −2 in alkaline, acidic, and neutral electrolytes, respectively, which is comparable to commercial Pt/C. Theoretical calculation demonstrates that the interfacial bridging-induced electron redistribution optimizes the free energy of water dissociation and hydrogen adsorption, resulting in improved hydrogen evolution. This study not only provides a novel electrocatalyst for efficient HER at all pH conditions but also opens up a new avenue for designing highly active catalytic systems.

Methanol upgrading coupled with hydrogen product at large current density promoted by strong interfacial interactions

“…Different M-O-M units can establish interfacebonding channels to enhance charge transfer, modulate the charge state of the surface adsorbate to activate reaction intermediates, and mediate the selectivity or activity of hybrid catalysts involving multiple transition pathways. [16][17][18][19][20] Therefore, searching for a matching M-O-M bond is a potentially effective solution to improve the synergistic catalytic performance. Considering that Fe 2 O 3 possesses half-fully occupied 3d orbitals and a flexible spin state, the construction of Ni-O-Fe pairs might well generate directional electron transfer from Ni-3d to Fe-3d orbitals, which consequently results in a strong interaction at the oxide interfaces.…”

Ni, Co, and Yb Cation Co-doping and Defect Engineering of FeOOH Nanorods as an Electrocatalyst for the Oxygen Evolution Reaction

“…The high-resolution XPS spectra of Co 2p (LMM: 774.87 eV; 2p 3/2 : 781.22 eV; 2p 1/2 : 797.17 eV) and Ni 2p (2p 3/2 : 856.03 eV; 2p 1/2 : 873.63 eV) in Ni,Co–FeOOH/CC correspond to typical Co­(II)–OH and Ni­(II)–OH, − confirming that the doping with Co and Ni replaces Fe in the form of divalent cations (Figure e,f). The positions of the characteristic peaks of Co 2p and Ni 2p in Ni,Co,Yb–FeOOH/CC do not shift compared with Ni,Co–FeOOH/CC, indicating that Co and Ni remain the divalent cation after doping with Yb.…”

Ultrafast Combustion Synthesis of Robust and Efficient Electrocatalysts for High-Current-Density Water Oxidation

“…After the OER cycling, the nanosheet structure of IF-Ni 150 mM is well preserved, further confirming the favorable electrochemical durability of the catalyst (Figure S18, SI). 53 The roughening of the outer edges can be attributed to partial electro-oxidation at high voltages. In addition, the IF-Ni 150 mM nanosheets showed distinct lattice streaks at the edges after the durability test attributed to the (102) crystal plane of hydroxy nickel oxide, which was consistent with the XRD result (Figures S19 and S21 (EDX) spectra presented obvious Fe, Ni, and O signals, and elemental mapping revealed that these species were uniformly distributed in the entire catalyst (Figure S20).…”